1. Field of the Invention:
The present invention relates to an improved building block and specifically to a building system including such a block.
2. Description of the Prior Art:
General concrete block construction offers durability, longevity, and other unique advantages for construction industries in all countries of the world. Block construction of this type is especially suited for many developing nations where a substantial number of structures are built according to this technique. The existing industry standard concrete block has one or more internal cavities and is planar on all six sides. The blocks are layed up by placing concrete mortar by the trowel method and then shoving and inserting the blocks into the mortar to obtain a bond between mortar and block. Succeeding courses of blocks are layed upon the first course of blocks after mortar is placed along the upper faces and the end walls of the previously layed blocks, resulting in a solid wall mass unit.
The previously described technique of laying concrete blocks produces a wall which is true vertically and horizontally and has the requisite strength. However, a shortage of craftsmen skilled in the technique exists around the world. Because of technical personnel shortages and consequent expense of such construction, concrete block construction has not seen the full utilization which would be expected.
Due to the shortcomings of the prior art construction techniques, various interlocking or mortarless blocks have been proposed. The theory is that interlocking blocks can be layed one upon the other, to lay up a wall without the necessity of skilled tradesmen to align the blocks one upon the other, to apply the mortar, and to position the blocks appropriately.
The mortarless or interlocking blocks known at the present time have various shortcomings. Many such blocks are so complicated in design that very precise molding or other forming techniques are required, raising the cost of the blocks beyond practical limits. Because of the complicated profiles employed, the block internal cavities have generally been of limited size, thereby restricting the passage of wiring or plumbing materials through the block interiors. Other prior art techniques have failed to provide blocks useful both as corner blocks and end blocks, thus requiring several different block designs to complete a single construction project.
The known prior art mortarless blocks are not truly "interlocking", but rather restrict movement in one dimension only. As a result, no design tables or handbooks exist for determining wall strengths for such wall systems. Such systems will not be acceptable for the construction of structures in countries having established building codes or other applications requiring wall strength calculation and certification. Existing locking tab systems are unreliable in their connections, making it difficult to predict their performance under uncontrolled conditions.
The present invention has as its object to provide a wall forming system made up of blocks which can be layed up, with or without mortar, by relatively unskilled workmen, thereby reducing the cost of building erection.
Another object of the invention is to provide a wall forming system which reduces the number of block types required to build a given structure.
Another object of the invention is to provide a wall forming system having an internally keyed indexing system and a mortar receiving internal recess, whereby a wall can be erected which is true horizontally and vertically and which possesses the necessary structural strength to meet existing building codes.
Another object of the invention is to provide an internally bonded block system that resists failure and maintains wall integrity even where cracks occur upon wall movement due to environmental forces.
Additional objects, features, and advantages will be apparent in the written description which follows.